download pdf

134 American Seashells
Littorina scutulata Gould Checkered Periwinkle
Alaska to Lower California.
Plate 20C
% inch in length, moderately slender, semigloss finish and smooth. Color
light to dark reddish brown with small, irregular spots of bluish white. Colu-
mella white; interior of aperture whitish brown. A common littoral species.
Compare with L. planaxis.
Littorina planaxis Philippi Eroded Periwinkle
Puget Sound to Lower California.
Plate 2oa
^ to % inch in length, usually badly eroded; grayish brown with bluish
white spots and flecks. Characterized by the eroded, flattened area on the
body whorl just beside the columella. Interior of aperture chocolate-brown
with a white spiral band at the bottom. A common littoral, rock-loving spe-
cies. Do not confuse with the smoother, higher-spired L. scutulata.
Littorina sitkana Philippi Sitka Periwinkle
Bering Sea to Puget Sound, Washington.
Plate 2ob
% inch in length, solid, sharp lip, characterized by about a dozen strong
spiral threads on the body whorl. Columella whitish. Shell dark grayish to
rusty-brown; some with 2 or 3 wide spiral bands of whitish. A common
littoral species of the north.
Genus Nodilittorina Martens 1897
Nodilittorina tuberculata Menke Common Prickly-winkle
South Florida, the West Indies and Bermuda.
Plate 191
^ to % inch in length. Shell rounded at the base. Several spiral rows
of small, fairly sharp nodules on the whorls. Columella flattened, forming a
slightly dished-out shelf. Color brownish gray. Operculum paucispiral. A
common rock-dwelling species found near the high-tide line. Do not con-
fuse with the extremely similar Echifiinus nodulosus Pfr. which has a multi-
spiral operculum, and whose columella is not shelved. Erroneously listed in
Johnsonia and other books as Tectarius tuberculatus Wood.
Genus Tectarius Valenciennes 1833
Subgenus Cenchritis Martens 1900
Tectarius muricatus Linne Beaded Periwinkle
Lower Florida Keys, the West Indies and Bermuda.
Plate iQg